This invention relates to contact conductors used to provide electrical power to vehicles, such as electric trains, trams, trolley buses and the like.
In the past, hard drawn copper or copper alloy wires have been used for vehicle contact conductors because of the high electrical conductivity and corrosion resistance of copper. Because of the high price of copper, there has been a need for a satisfactory contact wire made from other metals, such as aluminum.
While aluminum has good electrical conductivity, its strength and wear resistance are relatively low. To solve this problem, particularly for overhead contact wires, it has been suggested to use a steel wire sheathed in aluminum so that the steel wire can provide the necessary strength while the aluminum sheath provides good electrical conductivity. U.K. Patent Application 2,143,190 published Feb. 6, 1985, describes such a composite conductor having a steel core completely enclosed within an aluminum alloy outer covering, with at least the contact surface of the conductor being formed of a wear resistant aluminum alloy containing silicon, nickel and cerium for wear resistance.
German OS 3,437,871, published Apr. 25, 1985, describes a contact rail for providing power to an electric vehicle in which the contact rail is made of an aluminum-silicon alloy typically containing about 10 to 13.5% by weight of silicon. The alloy also preferably contains 0.2 to 1% magnesium.
It is the object of the present invention to provide an improved contact conductor, particularly an overhead contact wire, having sufficient tensile strength that it can be made entirely of an aluminum alloy without the need of a steel reinforcing wire.